Glass 101

OK guys, I think we kinda need this thread, I'm seeing people ask about some of the basics of glass terminology fairly regularly, and I know I would've found this useful before I got into glass, as it was kinda daunting with the amount of stuff I didn't know...

With that said, here's my beginnings of your one-stop-shop for glass terminology
Feel free to post anything you think I missed, I doubt this list will ever be complete

Glass on glass/GonG - a style of bong/bubbler where all connections are ground glass.

Ground glass - a type of finish on glass that will give an airtight seal.

Downstem - a glass tube that is inserted into a bong/bubbler to allow vapor to be brought below the water level of the piece.

Stemless - a style of bong/bubbler that does not use a downstem.

Grommetted - A style of bong/bubbler where the downstem is inserted through a rubber grommet to create an airtight seal.
Generally the downstem will be made of metal, and a grommetted piece will tend to taste worse than a GonG piece.

(14/14.4)mm & (18/18.8/19)mm - this refers to the size of the ground glass joint. The numbers in brackets all refer to the same size.
Adapters can be found to reduce or enlarge either of these joint sizes for under $20.
10mm is a less common, smaller joint size, and 23mm is a less common larger joint size.

Low profile/Bushing (joint) - A style of joint where the female joint is the next size down from the male joint, and sits inside the male joint.
This is most commonly seen in 18mm to 14mm reducing adapters, and some downstems that come with 18mm tubes.

Percolator/diffuser - somewhat interchangeable.
Diffuser seems to be used more for a downstem that has slits or some other type of diffusion.
Perc tends to be used more for diffusers that are fixed in place within a bong/bubbler, or for a diffuser that is in its own separate chamber.

Dewaar - a type of ground glass joint where the end of the joint sits flush with the surface of the glass.
There is no major functional difference between a dewaar joint and a regular joint.

Straight tube - A style of water filtration where the piece is essentially just a straight tube, often with a downstem.

Beaker - mostly the same as a straight tube, but has a flared out base, quite similar to a scientific flask (and ironically enough, nothing like a scientific beaker)

Bubbler - tend to be on the smaller side, more so designed for use while being held (as opposed to some larger tubes that are best used sitting on a flat surface).

Sandblast(ed/ing) - a process where sand is shot at the glass at a very high speed.
This leaves a cloudy texture on the surface of the glass, and can be used to add artistic patterns/designs to a piece, or as a alternative way to add logos to a piece.

Bore - the diameter of glass tubing used in a particular section of a glass piece.
e.g. 50x5 would be glass tube that has a 50mm diameter, with 5mm thick glass.

45/90 degree - the angle of the male ground glass joint on an ash catcher. A 90 degree joint is vertical, while a 45 degree joint is at an angle.

Ash Catcher (a/c) - An additional chamber that can be added to a water piece. It can be used purely to keep other water pieces clean (this is more so a factor for combustion), or to add another level of diffusion to an existing piece.

Showerhead - A tube with slits cut vertically at the end

X-Arm/Finger/Tree - A series of vertical tubes, often with 2-3 horizontal slits cut in them.

Inline - A horizontal tube with slits cut in it.

Stemline - A variation of an inline perc.

Glycerin (coil) - a style of cooling, where a tube of glass is set within another, larger tube, and the gap between them is filled with glycerin.
This can then be put in the freezer, so the glycerin will cool the vapor as you inhale it through the inner tube.

Disc (diffuser/perc) - a style of perc most commonly seen on stemless pieces, the style will change from piece to piece, but it is basically a glass disc that is the same diameter as the tube, with some holes in it to let the air through.

Natural perc: the name given to a style of tube that has no perc or diffy.
IMO, it's a misleading name, as there's nothing there .

Scientific: a style of glassblowing where the tubes are clear, without many fancy colors or sculpting etc.

Heady: a style of glassblowing where the tube can have different colors/patterns in it, pieces may be sculpted etc.
Generally more expensive than scientific stuff.

Keck clip: a (most commonly) plastic clip, designed to hold a male and female GonG connection together.
Different sizes are available for the different joint sizes.
Note: keck clips don't seem to be available for low profile joints.

Bore - the diameter of glass tubing, sometimes referred to as "wall", used in a particular section of a glass piece.
e.g. 50x5 would be glass tube that has a 50mm diameter/wall, with 5mm thick glass.

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Scientific: a style of glassblowing where the tubes are clear, without many fancy colors or sculpting etc. Often have diffusion/percolation based on scientific methods.

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Keck clip: Commonly a plastic clip, though often seen made of metal, designed to hold a male and female GonG connection together.

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While I'm not a fan of Natural percs and I understand what you're saying with, "nothing there". I think that's misleading, because it leads people to believe there really isn't any percolation. I've seen a few pieces, that perc pretty nice, for "nothing". I've seen a better example of this, but can't find it, right now. These do show a nice level of diffusion and functionality, however.

Click to play YouTube Video

Click to play YouTube Video

Natural perc: While no method of percolation is apparent, diffusion/percolation is achieved by water/vapor being separated by water levels in bends and/or chambers, in the glass.

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As much as I dislike Custom Creations... I've seen some of their natural percs, do some incredible percolation, climbing up the tube.

It should be said that if you're serious about learning about functional glass art you should check out www.tokecity.com , they are the original and have the largest population of experienced glass collectors. There's also www.glassdistrict.com which was started by a former TC member, but it seems to be dead lately. With that said, it's great to learn with friends and we are among friends here.

stonemonkey55 posted this in another thread, which was originally posted on another site. It's written with smoke in mind, but most of the concepts translate if you replace smoke with vapor. Some of it is a bit dated with things moving as fast as they have, still a good read.

The very basics: filtration, smoke volume, drag/turbulence.
In my opinion these are the three basic features of a piece that effect how enjoyable/smooth the smoke is. How much filtration, how much volume, and how much drag is acceptable is personal preference of course but these factors will always have significant impact. The more water the smoke has to flow through, the smoother the smoke. Water to smoke surface area contact removes the aqueous components from the marijuana smoke thus making it smoother and healthier than direct combustion. Smoke volume is fairly obvious, there is a certain volume of smoke that each individual can comfortably inhale and exhale without a dying cough.

Drag/turbulence play a role while inhaling to burn the bowl and when clearing. Too much drag when milking could lead to embarrassing drool and if there's drag when clearing, it increases the time the smoke is exposed to air (making it harsher and stale) and increasing the amount of time the smoke comes in contact with the lungs (longer delay would make it more irritable to the lungs).

Know origin of production
This is not to say that the country of origin has a direct impact on the quality of the piece, however certain countries have reputation for better quality control than others and this seems to hold true majority of the time. The three main countries relevant in this discussion are China, Germany, and the USA.

China is the king of mass production, and pieces originating from China are just that, mass produced glass products. This is particularly not well suited for glass piece production. With the fragility of glass and all the removable components that must fit in joints with little tolerance, the quality control applied by the manufacturer are usually sub par, delivering products that can break easily or perform poorly. This is not to say that all pieces from China are weak and poorly produced, but one should keep in mind the production process that leads to the final product. I’ve owned “China” glass that were free of imperfections and performed wonderfully, it is just up to the purchasing individual to apply his/her own strict quality control standards, which is why I’ve attempted to create this guide.

I don’t want to start a debate between Germany vs. USA (this really applies only to the ROOR brand) but the general consensus seems that products originating from these two countries have better quality control than China. That said, I have seen pieces from the USA that were produced poorly, so country of origin is never an end-all mark of quality.

Know artist/company who produced the piece
Brand and artist reputation isn’t everything, but very important. Don’t purchase a piece with bad reputation hoping that you’ll be the exception. I personally like to try to support local glassblowers who truly view pieces as art and not just glass to make money

Straight Tube vs. Beaker
The physical differences between the two are pretty obvious, one is a straight cylindrical tube whereas the other has a flask bottom base. Due to the streamlined design of straight tubes, they will always clear faster than their beaker counterparts. One thing to look for in straight tubes is the thickness and diameter of the base, as this translates to its stability. Tubes are generally more durable than beakers because of their design (a bump usually will contact the base vs. the beaker which can shatter). Some companies blow out the beaker straight from the tube and causes paper thin bottoms. Keep an eye out for beaker bottom thickness as well as tube thickness.

Thickness of glass
Check the thickness of the glass to see how durable it is. Pieces usually range from about 3mm to 9mm. The thickness of glass doesn’t necessarily mean it’ll be harder to break. What breaks glass? Force. Force = mass x acceleration. Thicker glass means you’ll be increasing mass which will increase the overall force. Thicker glass may be more durable to smaller bumps and such, but if it falls or tips there’s a greater chance it will break.

People always hit thicker glass tubes and claim that the smoke is smoother. This is true and not true at the same time...more discussed in the next section...

Outer/Inner diameter of tubing
Most glass tubing used in pieces come in a standard outer diameter of 50mm. As glass gets thicker, the outer diameter usually stays fixed and the inner diameter becomes smaller. This is why given two tubes of identical design but differing thickness of glass, the thicker will appear smoother to the user (less volume).

There are glass blowers that use different diameter tubing such as 40mm and also some companies (I know ZOB has done this) produce thicker glass with bored out centers so the smoke volume isn’t changed. I’ve also heard of glassblowers who “work down” tubes to make them shorter but thicker. I’m not 100% familiar with this process maybe someone can chime in.

If what you say is true, and that the OD of the tube remains the same regardless of wall thickness when sold to a blower, then two identical 18" 50mm straight tubes, one with 3.2mm thick walls and one with 9mm walls should differ in volume by about 314.9 mL.

Tube A:
OD: 50mm
ID: 43.6mm (3.2mm wall thickness)
H: 18"
V: 682.6 mL

Tube B:
OD: 50mm
ID: 32mm (9mm wall)
H: 18"
V: 367.7 mL

I didn't actually think the wall thickness would effect the interior volume that much, but I guess it does to some degree.

To help you visualize the difference, by choosing thicker walls, the ~315mL difference calculates out to an extra ~8.3" of the 50mm bore, 3.2mm wall tubing.

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Quality of joint
The ground glass joints featured on these pieces also come in differing quality. This is arguably the most stressful location on the piece. They come in different thicknesses but can roughly be categorized to “standard”, “bistabil” (what ROOR uses), and some super thick joints like “honalee” or "uber"

14mm vs. 18mm vs. 24mm This refers to the ground glass joint diameter used in pieces. The differences are pretty obvious, an 18mm will clear faster than a 14mm due to increased airflow. Arguably, a 14mm will allow you to produce a more concentrated hit, but this difference is usually not noticeable. 14mm tend to be cheaper than 18mm counterparts. 24mm joints can also be found in some "heavy hitter" pieces. Just like the difference between 14 and 18, a 24 will clear faster than both 14 or 18.

Also, joints come in varying qualities (both the male and female end) so make sure the joints are clean, free of imperfections, and slide easily in/out without much resistance or slack.

Quality of joint weld
looking at the joint from top down, look at the thickness of the glass around the joint. I wish I had a picture to point out exactly what I’m referring to but look right around the base of the joint (it kind of looks like a large oval when directly looking at the joint from the front of the piece)

Quality of glass (bubbles)
check the glass itself to see if there are any air bubbles, especially around key stress points like the joint. these can weaken the structural integrity of the glass

Lines of tube (make sure everything is perpendicular)
This might seem like a moot point but I’ve seen many beakers and straights that don’t sit perpendicular to the bottom. it doesn’t really effect smoking dynamics (unless the lean is so bad it throws off the perc water levels) but is indicative of the quality of production.

Ash catcher compatibility (compare joint angles of female piece and male a/c)
You wanna make sure that the reservoir of the ashcatcher sits parallel to the base of the piece to ensure maximum diffusion and minimal splashback. Try to see if the design of the ashcatcher is tall enough to prevent this, or if there is some type of splash guard integrated into the design.

Large pieces with carbs:
I'm not referring to bubblers and pipes but large glass pieces. Drilling that carb hole jeopardizes the structural integrity of the glass and becomes a super weakspot in the design.

Standard Downstem
This is your typical downstem that comes stock with most pieces. Just a simple tubing with ground glass joint. It tends to be "chuggy" but usually clears the fastest of all downstems

Slit Diffused Downstem
These are probably the most common type of diffuser downstem. The smoke travels down the tubing like any other downstem but exits the tip of the downstem through small slits cut along the sides. Look at the number of slits, how large the slit is, and how large the hole at the end of the downstem is to get a good idea of its diffusion capability and how draggy it'll be.

German-style Diffused Downstem
These downstems are also very popular and feature a tip that is pierced with small holes. Sometimes the holes are placed in straight bands around the stem, sometimes randomly, and sometimes as a spiral. They arguably provide better diffusion as the smoke is forced to travel out a greater # of openings but can also add significant drag if not designed properly. Check the number of holes, diameter of hole, and diameter of hole at the very tip to see how draggy it is.

Gridline Downstem
Sovereignty has a design they call the "gridline downstem". It's more of a modified german-style downstem as it feature small pierced holes in a grid like fashion on only one side of the downstem. The hole at the end is relatively large to allow for quick clearing.

Percolator Styles
Percolators serve to break down the smoke into smaller components and forcing them through water filtration again to provide additional filtration and cooling. They come in a variety of designs which all employ the same principle but in many different ways. Off the top of my head (and the designs I understand) I can think of these types of percs: Inline, Tree, Dome, Circulator, and Disc/Natural. I cannot tell you which perc is better than another because alot of it depends on the design of the particular perc in question

There are common traits in perc's to look for. They typically are the source of most drag in a poorly designed piece. Check the upstem diameter to see that there is enough flow and see how many # of slits are placed (whether it be around the dome or on each arm)

Inline/halo
I decided to group halo percs with inline percs as they both force the smoke to travel laterally through diffusion slits (maximizing surface area contact smoke:water ratio). In theory these should filtrate the smoke most (compared to say a "normal #" of tree arms) However ZOB's halo left much to be desired and the Inline designs coming out these days are significantly better in performance.

Tree
Tree percs work by directing the smoke stream through a upstem which then is forced 180* down back via separate glass arms into another reservoir of water where it is filtrated and continues up the tube. Check to see the # of tubes, how well the joint is that holds all the arms, and the thickness of each tube. There are small differences that can lead to different smoking dynamics such as the # of slits per arm or whether the bottom of the arm is sealed/opened/slit.

Dome
Dome percs work similar to tree, featuring an upstem that is then covered by a "dome" which has slits on the side. Since the dome is sealed over the upstem (minus the slits) the smoke is force to travel up the upstem and then back down inside the dome and exit out of the slits through water and up the tube. One thing to look for in particular is the distance between the upstem and the top of the dome. I've seen many production pieces that have very little clearance between the upstem and top of the dome which creates a restriction in air flow, translating into more drag. I believe this is the key weakpoint in dome percs

Circulator
Circulators can be considered the latest generation of dome percs. Instead of featuring 4 or 5 slits around the circumference of the dome, these percs feature many many tiny slits. This provides more diffusion and with the many # of slits increases the air flow and reduces the turbulence.

Disc/Natural
These operate by having the water level place below a solid disc with holes cut into (sometimes circular, sometimes triangular). As the vaccum is created when inhaling, it forces both the water and smoke to be sucked up through the holes in the disc as it filtrates. The cool thing about this design is once the entire bowl is milked, since the water level is now above the disc it is very easy to clear with minimal drag. My only complaint I've seen is that sometimes a disc perc by itself is a little chuggy and there is this initial difference in water pressure one must overcome before starting to milk

Gridcap
From my limited experience in hitting a gridcap, I would say it is a mixture of a dome perc and natural perc put together. Instead of a disc with various holes placed on its surface, there is a dome with multiple holes pierced all throughout the dome (around and above). It provides significantly more filtration than a disc perc. I've only seen this incorporated as the initial filtration (in replacement of a traditional downstem). One thing I noticed is there still is that water pressure difference the user needs to overcome before it starts to milk (if you don't understand what I'm saying, think like a few milliseconds of drag as the water levels rise above the dome but then it becomes dragless from that point on forward)

Gridline
These feature a fixed stem style except multiple downstems are placed horizontally across the base of the tube at the same level. Diffusion slits are cut on the top of these downstems. One could think of this as a quasi-inline sort of piece as it forces the smoke to travel laterally. As of now this design is exclusive to Sovereignty glass and I must say it performs very very well.

Fixed-Stem
Instead of having one downstem connect the bowl to the base of the piece, these have a tree perc attached to the downstem. As you can imagine, this provides significantly more filtration than a single diffused downstem.

Stemless
These have a straight tube that connects the bowl and bends 90* to connect to the reservoir of the tube. the ground glass joint for the slide is placed above the 90* bend so water levels never interfere with the bottom of the slide. These have that same initial water displacement you have to overcome before a smooth milk, but it clears super fast since. Some companies have placed diffused "caps" over the top of the water level to try to reduce the "chugginess" of the hit

Video comparing some different perc styles.

Click to play YouTube Video

Protective Measures
so you just spent you life savings on a Toro...how are you going to protect it?

The Keck "K" Clip
This little plastic clip is used in chemistry labs when carrying out reactions under pressure so that separate glass components don't disconnect and fly off each other from the built up pressure. In the smoking world, it does the same job, ensuring that the ashcatcher doesn't disconnect from the downstem, or the downstem doesn't disconnect with the main piece. A good number of glass piece accidents occur when there is some remaining moisture at the end of the slide causing it to stick to the downstem female joint and pulling the entire assemble out. Since the diameter of the joint is usually only a few milimeters greater than the downstem itself, it is easy to break the joint by pulling the downstem too much to the side. It also prevents the "dry" hit which to me isn't very enjoyable. In chem labs they usually only come in the blue color but other companies have started to produce generic clips in different colors so you can pick and choose to color coordinate with your piece.

Clips come in different sizes to accommodate the different joint sizes available in pieces 14mm and 18mm. With some pieces that have uber thick joints, I've resorted to boiling the K-clip for a few minutes and slowly stretching it by hand until it snugly fits over the joint without too much resistance (last thing you want is to break your own joint with something thats placed there to protect it lol)

Soft Padded Cases
These cases are good for carrying pieces around, however they still need to be handled carefully as hard knocks can still damage the piece. The two brands I've come to know are Magic Tailor bags and Vatra bags. Let me know if you guys know any other quality brands.

Hard Padded Cases
These hard cases are the ultimate protection from your piece. The industry leader is Pelican cases which is used by all sorts of ppl including photography professionals to soldiers on the battleground. They are expensive but provide a vacuum sealed protection from all the elements.

generic hard plastic cases are also available from various stores online. The key thing to look for is the cubed-foam, which makes it really easy to customize the foam to fit snugly around the piece. For storing slides, a good protective case are pistol hard cases.

@BDV
Re. the Natural perc
(this was the reason i threw the "IMO" in there ) I just think it's dodgy to call something a perc when you haven't constructed any kind of perc...

Is a non-diffused downstem in a straight tube a natural perc?
Can I say my DG pieces (or any disc diffused piece I guess) are natural perc to disc perc?
If so, then I'd say it's kinda a useless definition, since any non-dry pipe will have some form of percolation...

The way I see it, Those pieces you listed were a bubbler, and a tube, with no percs.
At a certain point, I could see a glassblower using natural perc fundamentals to make a nicely diffused setup, but I'd think ther'd be enough work in it for it to deserve it's own name...
A good example is my "pillar" bub by blissful glass.

IIRC (I'm still waiting on shipping), it's basically a "natural perc", but the water travels up 2 pillars, giving it somewhat of a pillar action.
I've got no objections to calling it a form of pillar perc, since it's at a point where more is going on than "water went around a U-bend".

I didn't mean for it to sound like no diffusion was happening with a natural perc though, so thanks for clearing that bit up

The last ten years or so have been an exciting time in the world of glass. There have more advancements in vaporization, glass etc. in the last 10 years than there ever has been. This is especially true for the last 5 years of so with the crazy vape and perc development.

With all the new stuff comes a lot of new information and terminology. It's pipology, lol.

OK guys, I think we kinda need this thread, I'm seeing people ask about some of the basics of glass terminology fairly regularly, and I know I would've found this useful before I got into glass, as it was kinda daunting with the amount of stuff I didn't know...

With that said, here's my beginnings of your one-stop-shop for glass terminology
Feel free to post anything you think I missed, I doubt this list will ever be complete

Does anyone have tips on glass usage/maintenance? I've read a lot, but I'm actually a total noob when it comes to using glass. Can y'all share any good tips?

Seems like I've heard somewhere before people saying it's better to rock a stuck joint back and forth to get it out instead of twisting/rotating to get it loose--helps prevent breakage(?). Or maybe I have that backwards? What's best?

I've also heard of people using "joint wax". Is that actually a good idea, since it keeps the joints from sticking? Or does it just make that issue worse? If it is a good idea, would something like the waxes often included with log vapes work as a wax for gong joints? What about that Chroniseur grinder wax stuff--could it be used effectively on gong joints?

Does anyone have tips on glass usage/maintenance? I've read a lot, but I'm actually a total noob when it comes to using glass. Can y'all share any good tips?

Seems like I've heard somewhere before people saying it's better to rock a stuck joint back and forth to get it out instead of twisting/rotating to get it loose--helps prevent breakage(?). Or maybe I have that backwards? What's best?

I've also heard of people using "joint wax". Is that actually a good idea, since it keeps the joints from sticking? Or does it just make that issue worse? If it is a good idea, would something like the waxes often included with log vapes work as a wax for gong joints? What about that Chroniseur grinder wax stuff--could it be used effectively on gong joints?

Any other tips from experienced folks greatly appreciated!

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I heard some olive oil was good to loosen up joints. I think SliM was telling me this.

Does anyone have tips on glass usage/maintenance? I've read a lot, but I'm actually a total noob when it comes to using glass. Can y'all share any good tips?

Seems like I've heard somewhere before people saying it's better to rock a stuck joint back and forth to get it out instead of twisting/rotating to get it loose--helps prevent breakage(?). Or maybe I have that backwards? What's best?

I've also heard of people using "joint wax". Is that actually a good idea, since it keeps the joints from sticking? Or does it just make that issue worse? If it is a good idea, would something like the waxes often included with log vapes work as a wax for gong joints? What about that Chroniseur grinder wax stuff--could it be used effectively on gong joints?

Any other tips from experienced folks greatly appreciated!

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If you just use your glass for vaping (no smoking or dabbing), cleanliness is very easy to maintain. There is wide variety of chemicals you can use for cleaning, however the most common by far, are Simple Green and isopropyl alcohol (the higher % the better). Unless you also use your piece for smoking/heavy dabbing, a few sprays of simple green will be adequate.

I typically only use alcohol when there is visible gunk caked on the piece (ie, reclaim). When cleaning, I first run hot water through the piece (hottest tap water available) until the glass is warm. Then I spray SG into both the mouthpiece and joint to ensure all interior surfaces are covered. I then rinse with hot water until all traces of SG are gone (suds, odor), and then transition into a cold rinse. Filtered/distilled water can help remove hard water stains, though I personally find this unnecessary.

For heavy cleaning:
[quick] First rinse with hot water until the glass is warm. Then add alcohol along with some salt (acts as an abrasive) and shake (making sure the openings are covered) until the piece is clean. Rinse with hot water and then transition to cold. I find this to be most effective cleaning method.

[slow] An alternative method is to plug the joint, and leave the piece soaking overnight in simple green. The next day, pour out the SG and rinse the piece out. If you want, the simple green may be saved and reused in future cleanings.

This is the stuff I use. Just soak it, then shake and wash out with tap water. Depending on how dirty my glass is, I just soak it for 1-12hrs. Warning do not use this on metal as it will discolor. For metal or TI I use 70% Alcohol only.

Do not use salt as a abrasive as it will scar your glass. Hot water will also burn in some of the resin into the pores of the glass and make it look cloudy or hazy permanently.

I have never used any of the wax products so I can't comment however I don't really see the need to use such a thing.

Does anyone have tips on glass usage/maintenance? I've also heard of people using "joint wax". Is that actually a good idea, since it keeps the joints from sticking? Or does it just make that issue worse?

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The post is from a while back i know,but since i've only just now read it...
I use silicone grease on the downstem connection of my Verdamper,which prevents it sticking very well.
Only on the downstem btw,this because that's the only connection,which can get moisture in it(from normal usage).
The other connection on my Verdamper(both are of the 'ground glass variety,the whole thing is also 'scientific' glass) stays dry,so doesn't require it.